On Fri,8/5/2016 11:03 PM, Richard (Rick) Karlquist wrote:
No, this isn't the real deal. A 2 port vector network analyzer
with full 2 port calibration is the real deal. The wattmeter
approach has many error effects that are difficult to account
Right. I've never considered using wattmeter(s) to measure loss in coax.
Now I use a DG8SAQ-designed VNWA (vector network analyzer). Very good
Before that, I used an HP generator as a source and an HP Spectrum
Analyzer as an RF voltmeter. Using that for measurement, I could clearly
see variation in the apparent loss below 2 MHz -- this was as a result
of the mismatch between this coax (Zo of a real line is complex and
varies with frequency) and the constant 50 ohm load and source
terminations. BTW -- I was measuring a sample about 1,200 ft long.
73, Jim K9YC
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